Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published March 2017 | Supplemental Material
Journal Article Open

A piezomicrobalance system for high-temperature mass relaxation characterization of metal oxides: A case study of Pr-doped ceria

Abstract

A system for mass relaxation studies based on a gallium phosphate piezocrystal microbalance has been developed, built, and successfully used to characterize a representative mixed ionic and electronic conducting material. The apparatus is constructed to achieve reactor gas exchange times as short as 2 seconds and temporal resolution in mass measurement of 0.1 seconds. These characteristics enabled evaluation of mass relaxations that occurred on the 6 seconds time scale. Proof of concept for materials characterization capabilities of the system was carried out using 10% praseodymium-doped cerium oxide (PCO), a material that undergoes, at selected temperatures and oxygen partial pressures, changes in mass but not in conductivity. Thin films were deposited on the piezocrystals via pulsed laser deposition (PLD). Mass relaxation curves were collected at 700°C upon application of a small step change in oxygen partial pressure, p_(O_2). Using two different films, the surface reaction constant, k_S, was obtained over the p_(O_2) range from 10^(−4) to 0.1 atm. Its value is found to vary between 9.7 × 10^(−6) and 1.7 × 10^(−4) cm/s, displaying a power law dependence on p_(O_2), with a law exponent of 0.67 ± 0.02, as averaged over the two sets of results. This steep dependence of k_S on p_(O_2) is surprisingly independent of a change in dominant defect type within the p_(O_2) range of measurement.

Additional Information

© 2016 The American Ceramic Society. Received: 18 July 2016. Accepted: 21 October 2016. Version of record online: 21 December 2016. Funding of this project through the California Institute of Technology EAS Discovery Funds Program is gratefully acknowledged. Support for T.C.D. was provided by an EERE Postdoctoral Research Award. The authors thank Haemin Paik and Anupama Khan for assisting with AFM measurements, as well as Fan Yang from the Joint Center for Artificial Photosynthesis for assistance with ALD. The authors furthermore thank the Caltech GPS Division Analytical Facility and NUANCE at Northwestern University for providing access to SEM and AFM instrumentation. P.S. thanks Prof. Aldo Steinfeld for supporting his research visit to the California Institute of Technology.

Attached Files

Supplemental Material - jace14652-sup-0001-FigS1.tif

Supplemental Material - jace14652-sup-0002-FigS2.eps

Supplemental Material - jace14652-sup-0003-FigS3.eps

Supplemental Material - jace14652-sup-0004-FigS4.eps

Supplemental Material - jace14652-sup-0005-Suppinfo.docx

Files

jace14652-sup-0001-FigS1.tif
Files (11.2 MB)
Name Size Download all
md5:453556157b412102994d77ab9a58578c
761.3 kB Download
md5:cd0b475f972b73a643e6d5a685c1fa41
6.7 MB Preview Download
md5:7f857fa112fe90e406ef71ec02dc14e8
128.7 kB Download
md5:978e93a566b5bc2948de28e483e5b0cf
1.7 MB Download
md5:6af5c00cafe7fd50121f9d43242651e0
2.0 MB Download

Additional details

Created:
August 19, 2023
Modified:
October 24, 2023